Sasidharan Salini, Bradford Scott A, Šimůnek Jiří, Kraemer Stephen R
Department of Environmental Sciences, University of California Riverside, Riverside, CA 92521, USA.
United States Department of Agriculture, Agricultural Research Service, U. S. Salinity Laboratory, Riverside, CA 92507, USA.
J Hydrol (Amst). 2021 Mar 1;594:1-125720. doi: 10.1016/j.jhydrol.2020.125720.
Drywells (DWs) and infiltration basins (IBs) are widely used as managed aquifer recharge (MAR) devices to capture stormwater runoff and recharge groundwater. However, no published research has compared the performance of these two engineered systems under shared conditions. Numerical experiments were conducted on an idealized 2D-axisymmetric domain using the HYDRUS (2D/3D) software to systematically study the performance of a circular IB design (diameter and area) and partially penetrating DW (38 m length with water table > 60 m). The effects of subsurface heterogeneity on infiltration, recharge, and storage from the DW and IB under constant head conditions were investigated. The mean cumulative infiltration (μI) and recharge (μR) volumes increased, and the arrival time of recharge decreased with the IB area. Values of μI were higher for a 70 m diameter IB than an DW, whereas the value of μR was higher for a DW after 1-year of a constant head simulation under selected subsurface heterogeneity conditions. A comparison between mean μI, μR, and mean vadose zone storage (μS) values for all DW and IB stochastic simulations (70 for each MAR scenario) under steady-state conditions demonstrated that five DWs can replace a 70 m diameter IB to achieve significantly higher infiltration and recharge over 20 years of operation. Additional numerical experiments were conducted to study the influence of a shallow clay layer by considering an IB, DW, and a DW integrated into an IB. The presence of such a low permeable layer delayed groundwater recharge from an IB. In contrast, a DW can penetrate tight clay layers and release water below them and facilitate rapid infiltration and recharge. The potential benefits of a DW compared to an IB include a smaller footprint, the potential for pre-treatments to remove contaminants, less evaporation, less mobilization of in-situ contaminants, and potentially lower maintenance costs. Besides, this study demonstrates that combining both IB and DW helps to get the best out of both MAR techniques.
渗水井（DWs）和渗滤池（IBs）作为管理含水层补给（MAR）装置被广泛用于收集雨水径流并补给地下水。然而，尚无已发表的研究在相同条件下比较这两种工程系统的性能。使用HYDRUS（2D/3D）软件在理想化的二维轴对称区域上进行了数值实验，以系统地研究圆形IB设计（直径和面积）以及部分穿透的DW（长度38米，地下水位>60米）的性能。研究了恒定水头条件下地下非均质性对DW和IB的入渗、补给及储存的影响。IB面积增大时，平均累积入渗量（μI）和补给量（μR）增加，补给到达时间缩短。在选定的地下非均质性条件下进行1年恒定水头模拟后，直径70米的IB的μI值高于DW，而DW的μR值更高。对稳态条件下所有DW和IB随机模拟（每个MAR场景70次）的平均μI、μR和平均包气带储存量（μS）值进行比较表明，5个DW可以替代直径70米的IB，在20年的运行中实现显著更高的入渗和补给。通过考虑IB、DW以及集成到IB中的DW，进行了额外的数值实验以研究浅层粘土层的影响。这种低渗透层的存在延迟了IB对地下水的补给。相比之下，DW可以穿透致密粘土层并在其下方释放水，促进快速入渗和补给。与IB相比，DW的潜在优势包括占地面积更小、具有去除污染物的预处理潜力、蒸发量更小、原位污染物的迁移更少以及维护成本可能更低。此外，本研究表明，将IB和DW结合使用有助于充分发挥两种MAR技术的优势。
